One of my FOB has stopped working, cannot lock the car anymore and needed to insert it in the slot to start it. Car is only a year old so kind of surprised the battery is dead.

Anyways I popped it open and saw replaceable battery. I called up my local dealer to see if they could replace it and they told me it is rechargeable and I just need to put it in the slot. Told him I had comfort access and he again he told me it is rechargeable. To me it looks like a standard replaceable battery that I assume does not charge. So what is up?